Scientifically, beetles belong to the Coleoptera, an insect order characterized by a pair of hard wing cases or elytra. These are believed to be the single most important feature that has contributed to the evolutionary success of beetles. These strong elytra grant the beetle an amour-like protection: when stepped on over soft ground, it is quite likely to be pushed unharmed into the mud, whereas other insects would be crushed. Beetles are also generally characterized by their biting mouth-parts. The word ‘beetle’ actually comes from the Middle English word ‘bityl’ or ‘betyll’ meaning ‘little biter’.
It could be said that the Creator must have been very fond of beetles. Or at least it would seem so because more than 400,000 species of insects are beetles, a significant two-fifths of all six-legged creatures. In comparison, there are a mere 44,000 species of vertebrates and some 250,000 species of known plants. Their diversity is not only evident in number, but also size, colour, pattern, form, as well as strategies of behaviour, defence, reproduction, and adaptation, already much appreciated since the time of the Pharaohs. Indeed, we live in the Age of Beetles!
Beetles are certainly important to study if we are to understand the diversity and ecology of insect fauna in various tropical habitats. Although somewhat diverse and ubiquitous in terrestrial habitats, they are less commonly encountered than moths, butterflies and ants. This is mainly because more than 95% of beetles are less than a centimetre long and they are often not found in swarms as one species like ants. Many are only active at night.
Borneo’s mesmerising natural biodiversity is made up of very many species, including beetles, and very many are also endemic or confined to this island. It follows that it is virtually impossible to attempt including all beetles in the present account. This pictorial guide covers more than 150 beetle species, including some of the most captivating or even inspiring forms known. To foster better awareness and showcase the high diversity of tropical beetles, we feature some large and interesting beetles as well as others commonly encountered in Borneo. More than a third of those featured in this book are endemic to Borneo.